Process of refining



Auge 24, 1943. B. H. THURMAN I. 2,327,569

PROCESS 0F REFINING Filed March 29, 1941 atented Aug. 24, 1943 UNITI-:DvSTATES PATENT oFFicE PBDCESS OF REFINING BenJamlnH.

. Nevada Thurman. Charlotte, N. C., assigner to Refining, Inc., Reno,Nev.,

a corporation of Appliqaion March 29, 1941, Serial No. 385,943

(CL 26o-425) Claims.

stantially instantaneous uniform distibution of the alkali through theoil. Such conventional mixing procedures result in the distribution ofrelatively large globules of alkali through the oil and the distributionof relatively large globules of oil through the alkali, the formerpredominating. The lalkali reacts with the fatty acids almostinstantaneously, lforming soap, which in turn emulsifies and envelopscrude oil particles. Also, unreacted alkali is enveloped in crude oil.Thus, there are areas of untreated crude -and of unreacted alkali,surrounded by soap layers. In due time and after prolonged stirring,some of these enveloped masses may be worked back into the bulk of thematerial, thereby permitting reaction. It will be apparent, therefore,that quantities of reactants are segregated from the reaction zone, andconsequently there can be no uniformity of reaction. Furthermore,because of the different manner in which fatty acids, phosphatids,coloring matter, and neutral oil react, it is possible to start onereaction without allowing the other to progress. For instance, if thealkali is not uniformly distributed instantly throughout the oil, theimmediate formation of soap not only shuts out crude oil but preventsthe other necessary reactions from proceeding in areas where uncombinedcaustic is no1; available.

Refining operations employing the above type of mixing require arelatively extended period of contact to complete the various phases ofthe rening. It will be apparent, therefore, that the period of contactbetween the oil and the alkali must be suflcient to permit, either bydiffusion or by continued agitation, contact between alkali and theimpurities and to permit reaction between them. This extended period ofcontact, while considerably reduced in the continuous operation overthat encountered in batch operation, is still sufficient to permitmaterial losses by saponiflcation and entrainment of neutral oil.

The present invention contemplates v the admixing of the oil and alkalisubstantially instantaneously. It has been found that by physicallydistributing the alkali through the oil at such a rate that distributionis accomplished before substantial chemical reaction has hadtime to takeplace with the fatty acids, that "all the rening re-Y actions can startsimultaneously throughout all the oil and will be complete much soonerthan in conventional refining processes. It has been found that thereactions of neutralization, hydration of the gums and phosphatides,absorption of color, and saponication of neutral oil occur at ratesdecreasing in the order named. Therefore, by securing completedistribution of the alkali through the oil before any substantial amountof chemical reaction takes place, the relining reactions ofneutralization, hydration and absorption of color can be completedbefore any material saponilication of neutral oil can occur. Also,degradation of phosphatides due to long contact with strong alkali ismaterially reduced. That is, the alkali is promptly used up in thedesired reactions or is promptly removed from the oil and is notretained in the mixture so as to be available for the undesirable slowerreactions for substantial periods of time..

It is, therefore, an object of the present invention to providel arefining process in which the oil and refining agent are thoroughlyadmixed substantially instantaneously.

It is another object of the present invention to provide a refiningprocess which results in decreased neutral oil losses.

A further object of the present invention is to provide an improvedrefining process Which permits the employment of a minimum quantity ofrefining agent.

A still further object of the present invention is to provide animproved process of removing and recovering phosphatidesin anundecomposed condition, VJ j Another object of the present invention ist9 provide an improved refining process in whicl the oil and therefining agent are substantially completely admixed physically beforechemical reaction begins.

These and other objects of the present invention will be apparent tothose skilled in the art from the following description of theinvention:

Crude animal and vegetable oils are composed principally of glyceridesof fatty acids, and in addition thereto contain small quantities of freefatty acids, gums, phosphatides, coloring matter and the like. It is theobject of the rener to remove these minor constituents and obtain, as

' far as possible, a substantially colorless oil composed solely of theglyccrides. Conventional rening includes the treatment of the crude oilwith aqueous solutions of caustic alkalies such as sodium hydroxide. Thesodium hydroxide reacts readily with the free fatty acids A.to formsoaps thereof. The gums and phosphatides hydrate readily in the presenceof water. In the presence of aqueous sodium hydroxide the phosphatidesbecome hydrated and lose some of their oleophilic character and thusbecome less soluble in oil. They do, however,v stillv retain powerfulemulsifying properties. The sodium hydroxide, however, then proceeds toreact with the phosphatide molecule to form what is believed to be anabsorption complex. This complex is even less soluble in the oil and toa large' extent has lost its emulsifying properties, and can be removedfrom the oil eiliciently by centrifugal force. In the course of timethis sodium hydroxide phosphatide complex decomposes into -sodiumglycerophospheric acid and other products. This decomposition is at arelatively low rate and probably occurs at a rate similar to that ofsaponiflcation of the neutral oil.

The color constituents of the crude oil are removed by means of causticalkali, probably by modification and adsorption by the soap. Thisadsorption is believed to occur at a rate less than the neutralizationof the free fatty acids and the formation ofthe phosphatide complex butat a faster rate than the saponiflcation of neutral oil. From the abovedescription it will be apparent that by physically distributingthe-alkali substantially uniformly through the oil before anysubstantial amount of chemical reaction can occur, the above reactionswill occur simultaneously and will be completed in the order of thereaction rates. It will thus be seen that the main steps of refining,namely the neutralization of free fatty acids, the hydration of thephos'- .phatides and the absorption of color, can be completed beforeany large quantity of the neutral oil has been saponied and phosphatidesdecomposed. By rapidly separating the aqueous phase containing theimpurities, from the oil phase after refining is complete, substantiallyall the neutral oil can be recovered in a relatively pure state.Similarly, by treating the separated aqueous phase containing thephosphatides in the alkali complex, with an acid, it is possible to stopthe decomposition of the complex and to recover phosphatides in asubstantially undecomposed form.

In Fig. 1 of the drawing there is shown a diagrammatic illustration ofone embodiment of the present invention. In this figure there is shown asupply of crude oil in tank I and a supply of refining agent in tank II.Each o1' these tanks may-be supplied with heat exchange coils I2 bymeans of which the temperature of the oil and the refining agent may besuitably adjusted. Measured quantities of the proportioned streams ofthe oil and alkali may be Withdrawn from 4tanks l0 and II by means ofpiunps I3 and I4 respectively. These pumps may be driven by a commonvariable speed motor I5. The variable speed mechanism I6 permitting thedesired proportioning of the streams of oil and alkali. The proportionedstreams may be mixed in a mixer I'I in which the alkali is uniformlydistributed throughout the oil in a substantially instantaneousmanner,to' be described hereinafter. The mixed stream of oil and alkali maythen be passed through the coil I8 disposed within tank I9 which maycontain a heat exchange medium for the purpose of conditioning themixture of oil and. impurities for the step of centrifugal operation.

`'I'he mixture is then discharged into centrifuge 20 in which it isseparated into soap stock and refined oil which are discharged throughspouts 2I and 22, respectively.

Fig. 2 illustrates av section through a mixer which has been foundsuitable for the present invention. This mixer is composed of a centralpipe 25 surrounded by a jacket 26 having a suitable inlet 21. Thecentral pipe 25 is provided with a large number of minute orifices 28which permit communication. between the jacket 26 and the interior ofthe pipe 25. These orifices are extremely minute and may, for example,be from .001 to .01 inch in diameter. The proportioned stream of crudevoil from pump I3 is passed through the pipe 25. The proportioned streamof alkali from pump I 4 is introduced into the jacket from the inlet 21.It is preferred to employ a large pressure dierential for example fromto 1000 pounds per square inch across the orifices 28. By means of thishigh pressure differential minute quantities o'f alkali in the form ofmist or spray distribute themselves through the body of flowing oil. Bymeans of this high pressure differential the mixing of the oil andalkali can be completed before any substantial amount of chemicalreaction occurs, It is preferred to spray the reagent into a movingcylinder of crude oil without disruptinging the body of the cylinder toany substantial extent by mechanical means. The reagent is broken intoextremely fine particles or droplets at the point where it is flashed orexploded into the fiowing mass of oil. 'Ihe particles of reagent havesuch a high velocity and possess so much kinetic energy that theypenetrate the crude oil and are dispersed instantly. In this Way thehigh velocity particles of refining agent break up the oil physicallybefore substantial chemical action occurs.

In thismanner the various refining reactions may be institutedsimultaneously and the resultant mixture of oil and impurities is readyfor separation when the absorption of color, apparently the slowestrefining reaction, has been completed. The mixture may be prepared forcentrifugal separation by heating to an emulsion breaking temperature orin any other manner.

Where it is desired to recover the phosphatides in undecomposedcondition, thedegradation of the phosphatides by the alkali can bestopped in several Ways, for example, by rapidly drying the soap stockor by neutralizing the alkali present.

Thus, the soap stock immediately after it has been separated from theoil may be dried, preferably in a vacuum, following which phosphatidesmay be extracted with a solvent such as benzol, petroleum ether, oramixture of benzol and alcohol. Alternatively the dried soap stock maybe treated with a solution containing' enough acid to neutralize thealkali, and then the phosphatides may be extracted with an oil solvent,

Another method is to extract the dried soap stock with acetone, whichremoves the oil, leaving behind the phosphatides and soap. Thephosphatides may be dissolved in an oil solvent, leaving behind thesoap. Or', the mixture of soap and phosphatides may be treated withenough acid to decompose the soap yielding ay mixture of fatty acid andphosphatides. mixture is capable of 'a number of uses w'itlout-hydrochloric or sulphuric, in amounts suiiicient to neutralize theexcess sodium hydroxide. A further method is to treat the soap stockdis- 3. The method of renning glyceride oils recovering phosphatidestherefrom, which comprises, mixing proportioned streams of oil and anexcess of a caustic alkali refining agent by flowing a substantiallyuniformly advancing stream of said oil through a passageway having asmall substantially uniform cross-section in suf- -ncient amount to fillsaid passageway, injecting charged from the centrifuge with a bariumchloride solution which serves to neutralize excess alkali. The actionof the alkali in the discharged soapstock may be stopped by means ofadding alcohol or alcoholic solutions of magnesium chloride.

By means of any of the above procedures the decomposition of the sodiumhydroxide phosphatide complex may be stopped. Furthermore, thephosphatide may be isolated from the soap stock mixture in any of theabove stated ways.

While the present invention is particularly adapted to the alkali reningof vegetable oils in view of the nature of the multiplicity of reactionsoccurring therein, the present method of mixing may also advantageouslybe used in other refining operations such as degumming, employing eitherWater oran electrolyte as the refining reagent, or in acid refining,since the present method of mixing obviates any disadvantage produced bytoo extended a contact of the rening ,agent with the neutral oil.

While various embodiments of the present invention have-been describedin detail, it is to be understood that the invention is not limitedthereto but may be varied within the scope'of the following claims: n

I claim:

1. The method of reninggglyceride oils, which comprises, mixingproportioned streams of oil and a refining agent by flowing asubstantially uniformly advancing stream of said oil through apassageway having a small substantially unlform cross-section insufcient amount to ll said passageway, injecting into said stream of oilthrough the walls of said passageway a plurality of minute high velocityjets Vof said rening agent, the cross-sections of-said jets andpassageway being sufficiently small and the velocity of said jets beingsufficiently great to cause said jets to penetrate substantiallyinstantaneously into all portions of said stream'to substantiallyuniformly distribute minute droplets of said reiining agent throughoutsaid stream, and promptly thereafter separating from said oil impuritiesprecipitated in said oil by said rening agent.

2. The method of refining glyceride oils, which comprises, mixingproportioned streams of oil and a refining agent by flowing asubstantially uniinto said stream of oil through the walls of saidpassageway a plurality of minute high velocity jets of said reningagent, the cross-sections of said :Iets and passageway beingsufficiently small and the velocity of s aid jets being sulclently greatto cause said jets to penetrate substantially instantaneously into allportions of said stream to substantially uniformly distribute minutedroplets of said renning agent throughout said stream, promptlythereafter separating from said oil soap stock including phosphatidesprecipitated in said oil by said rening agent, promptly thereaftertreating said soap stock to prevent attack on said phosphatides by saidexcess caustic alkali, and recovering phosphatides from said soap stock.

4. The method of refining glyceride oils and recovering phosphatidestherefrom, which comprises, mixing proportioned streams of oil and anexcess of a caustic alkali refining agent by flowing a substantiallyuniformly advancing stream of said oil through a passageway having asmall substantially uniform cross-section in suflicient amount to llsaid passageway, injecting into said stream of oil through the walls ofsaid passageway a plurality of minute high velocity jets of saidrefiningI agent, the cross-sections of said iets and passageway beingsuillciently small and the velocity of said jets being sumcien'tly greatto cause said Jets to penetrate substantially instantaneously into allportions of said stream to substantially uniformly distribute minutedroplets of said refining agent throughout said stream, promptlythereafter separating from said oil soap stock including phosphatidesprecipitated in said oil bysaid refining agent, promptly thereafterdehydrating said soap stock to prevent attack on said phosphatides bysaid excess caustic alkali, and recovering phosphatides from said soapstock.

formly advancing stream of said oil through a V passageway having asmall substantially uniform circular cross-section in suiilcientamount-to fill said passageway, injecting radially inwardly into saidstream of oil in a plurality of radial directions through the walls ofsaid passageway a plurality of minute high velocity jets of saidrelining agent, the cross-sections of said jets and pas.

sageway being sufliciently small and the velocity of said jets beingsuciently great to cause said jets to penetrate substantiallyinstantaneously into all portions of said stream to substantiallyuniformly distribute minute droplets of said refining v agent throughoutsaid stream, and promptly thereafter separating from said oil impuritiesprecipitated in said oil by said refining agent.

`5. The method of refining glyceride oils and recovering phosphatidestherefrom, which comprises, mixing proportioned streams of oil and anexcess of a caustic alkali rening agent by owing a substantiallyuniformly advancing stream of said oil through a passageway'having asmall substantially uniform cross-section in suilicient amount to fillsaid passageway, injecting into said stream of oil through the walls ofsaid passageway a plurality of minute high velocity :lets of saidrenning agent, the cross-sections of said jets and passageway beingsuiciently small and the velocity of said jets being sufcientlyfgreat tocause said :lets to penetrate substantially instantaneously into allportions of said stream to substantially'uniformly distribute minutedroplets of said refining agent throughout said stream, promptlythereafter separating from said oil soap stock including phosphatidesprecipitated in said oil by said refining agent, promptly Y thereafterneutralizing vsaid excess caustic alkali in said soap stock with an acidto prevent attack on said phosphatides by said excess ,caustie alkali,and recovering phosphatides from said soap stock.

yBENJAMIN H. 'I'HURMAN.

